Sealing tape

ABSTRACT

The tape is free from any slack and separation even when it is applied and bonded to a metal joint portion while being bent. The tape, made of an unvulcanized material containing an unvulcanized rubber-base material, a vulcanization accelerator, an anti-oxidizing agent, a pigment and a bulk filler, is formed into an elongated shape having an upper and a lower surface and a predetermined thickness measured in a direction perpendicular to the lower surface or flat bottom surface 1. The upper surface forms a circularly-curved surface 2 in cross section. Since the tape is in an unvulcanized state, it is capable of being free bent when applied to the metal joint portion. After application of the tape to the metal joint portion, a paint is applied to the tape, which is followed by a heating process in which the tape is heated, and, therefore vulcanized.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a sealing tape and a method andapparatus for its production, and a method of repairs with it, and moreparticularly to a sealing tape for covering, in a car body, an exposedmetal surface, a joint between metal plates, a shoulder portion injoint, and like stepped portions.

2. Description of the Prior Art

In the manufacture of automobiles, it has been the practice to apply asealing agent to joint portions and joint shoulder portions in carbodies such as body panel joints and hemming portions in door and hoodsof the car bodies to prevent water and dust from entering the carbodies. More specifically, as shown in FIG. 15, in case that an innermetal plate B is inserted into and jointed to a bent portion C of anouter metal plate "A" which is provided with the bent portion C in itsend portion, a joint shoulder portion D extending in a directionperpendicular to the plane of the drawing paper is covered with a stripof sealing agent E having been squeezed out of a tube through itsnozzle, so that the thus sealed joint shoulder portion D extends in thedirection perpendicular to the drawing paper.

The application of this sealing agent E to the car body is carried outby an industrial robot during the manufacture of the car or automobile.Consequently, it is possible to control, with high accuracy, both theamount of the sealing agent E being squeezed out through the nozzle anda traveling distance of the nozzle, which enables the sealing agent Ehaving been applied to the car body to assume a constant shape in crosssection, as shown in FIG. 14. The application of the sealing agent E tothe car body is followed by the application of paint.

When the joint of car body panels is deformed by an impact applied tothe car, it is necessary to repair such deformed joint so as to have thejoint return to its original shape in appearance.

In such repairing and paint application of the car body, aftercompleting the repair in shape of the joint of the car body panels, thesealing agent E is applied to the joint in a manner such that: thenozzle of the tube, which is made of, for example, metal and filled withthe sealing agent E, is manually brought into direct contact with ajoint of the car body by an auto worker; and, the sealing agent E isalso manually squeezed out of the tube through the nozzle thereof whilethe nozzle of the tube is manually moved along the course of the jointby the worker, whereby the application of the sealing agent E to thecourse of the joint is manually carried out by the worker.

In such manual operations, it is very difficult for the worker to keepconstant the amount of the sealing agent E applied to the course of thejoint even when he concentrates his attention on his work in which hemust constantly squeeze the sealing agent E out of the tube as he movesthe tube along the course of the joint. In other words, in most cases,the worker fails to accurately trace the course of the joint, whichresults in an uneven finishing surface of the sealing agent E thusapplied to the joint. Due to this failure, the joint of the body panelsthus repaired fails to assume the same shape as that of a joint of bodypanels in a new car. The shape of the joint in a new car is shown inFIG. 15 in cross section.

Previous to the present invention, the inventor of the subjectapplication has already proposed a conventional sealing tape 10. Thissealing tape 10 enables a user to seal the joint of car body panels withit in a very easy manner, and the joint thus sealed with the tape 10 isexcellent in finishing.

As shown in FIG. 14, the conventional sealing tape 10 assumes anrelatively thick strip-like shape with a stepped bottom surface, and ismade of vulcanized rubber material to resiliently keep its originalshape. In use, such conventional sealing tape 10 is adhesively appliedto a joint shoulder portion of metal plates (See, Japanese Utility ModelRegistration No. 3,004,875).

For example, as shown in FIG. 13, in application of the conventionalsealing tape 10 assuming the above shape to the joint shoulder portion Dlocated between the outer or first metal plate "A" and the inner orsecond metal plate B which is inserted into and jointed to the bentportion C of the first metal plate "A" which is provided with the bentportion C in its end portion, the sealing tape 10 has its first bottomsurface portion 11, which is opposite to a curved portion 14 of the tape10, and its second bottom surface portion 12, which is opposite to aflange edge portion 15 of the tape 10, adhesively applied to the metalplates "A" and B, respectively.

As a result, both the first bottom surface portion 11 and the secondbottom surface portion 12 of the conventional sealing tape 10 may firmlyadhere to the joint shoulder portion D located between the metal plates"A" and B, which ensures that the joint shoulder portion D issufficiently sealed up.

However, for example, as shown in FIG. 12, when the conventional sealingtape 10 is used in a joint shoulder portion of metal plates of an innerside of a car rear door (an upholstery lining panel of which is removedin FIG. 12), it is necessary to bend the sealing tape 10 atsubstantially right angles in a manner such that the sealing tape 10extends along a corner portion G of the door to adhere to the cornerportion G.

In this case, the sealing tape 10 often slacks in or separate from thecorner portion G of the door, which impairs the door in its surfacefinish quality. In order to improve the door in such surface finishquality, it is necessary to manually apply the sealing agent E to thiscorner portion G of the door as is in the conventional application.

The above-mentioned slacking and separation of the sealing tape 10occurs because of its resiliency. In other words, since the sealing tape10 is made of rubber material having been vulcanized and assumes astrip-like or elongated shape with resiliency, such slacking andseparation occurs in the corner portion G of the door. In general,rubber material is vulcanized to assume a fixed shape of a desiredrubber product, because rubber material not vulcanized may vary in shapeunder pressure. Consequently, such rubber material not vulcanized is notadequate for the purpose of the sealing tape which must keep its shapefor a long period of time in use.

SUMMARY OF THE INVENTION

Under such circumstances, the present invention was made on the basis ofthe fact that the application of paint in car repairs is accompaniedwith a heating process. Consequently, it is an object of the presentinvention to provide a sealing tape and a method and apparatus for itsproduction, and a method of repairs with the sealing tape which is anunvulcanized tape, and, therefore capable of freely varying in shapewhen required to bend, the method of repairs using the heating processto vulcanize this sealing tape.

According to a first aspect of the present invention, the above objectof the present invention is accomplished by providing:

A sealing tape made of a sealing-tape material containing anunvulcanized rubber-base material and its vulcanization accelerator, thesealing tape assuming an elongated shape with a bottom surface and apredetermined thickness measured in a direction perpendicular to thebottom surface.

Since the sealing tape of the present invention is in an unvulcanizedstate, it is capable of being freely deformed. Consequently, even whenthe sealing tape of the present invention is bent into a desired shape,there no fear that the tape slacks and separates from a portion to whichthe tape is applied.

According to a second aspect of the present invention, the above objectof the present invention is accomplished by providing:

The sealing tape as set forth in the first aspect of the presentinvention, wherein:

added to the unvulcanized rubber-base material together with thevulcanization accelerator is an anti-oxidizing agent.

The anti-oxidizing agent is capable of improving the sealing tape of thepresent invention in weatherability.

An adhesive may be applied to the bottom surface of the sealing tape,the unvulcanized state of which tape makes it possible to apply theadhesive to the bottom surface of the sealing tape.

According to a third aspect of the present invention, the above objectof the present invention is accomplished by providing:

The sealing tape as set forth in the first aspect of the presentinvention, wherein:

the bottom surface is a stepped surface which enables the sealing tapeto be brought into close- or hermetic-contact with a stepped joint orshoulder portion of metal plates.

According to a fourth aspect of the present invention, the above objectof the present invention is accomplished by providing:

A method for producing a sealing tape, comprising:

a sealing-tape material preparing step for preparing a sealing-tapematerial containing an unvulcanized rubber-base material and itsvulcanization accelerator;

a sealing-tape forming step in which the sealing-tape material is formedinto a substantially square-shaped sheet while keeping its unvulcanizedcondition;

an adhesive applying step for applying an adhesive sheet to a bottom ofthe substantially square-shaped sheet, the adhesive sheet being coatedwith an adhesive; and

a substantially square-shaped sheet cutting step for cutting thesubstantially square-shaped sheet into at least one of the sealing tapeseach of which assumes an elongated shape having a bottom surface and apredetermined thickness measured in a direction perpendicular to thebottom surface of the sealing tape, wherein the substantiallysquare-shaped sheet is moved while having its upper surface brought intopress-contact with a roll-type cutter provided with at least a pair ofcircular blades axially spaced apart from each other through an annularconcave portion formed in a peripheral portion of the roll-type cutter.

In this method for producing the sealing tape, the annular concaveportion of the roll-type cutter may be a circularly-curved shape incross section which is adapted for being used.

Further, in the method for producing the sealing tape, an anti-oxidizingagent may be added in the sealing-tape material preparing step. Theanti-oxidizing agent is capable of improving the unvulcanized sealingtape in weatherability.

According to a fifth aspect of the present invention, the above objectof the present invention is accomplished by providing:

A method of repairs with a sealing tape, comprising the steps of:

applying the sealing tape to a joint between a pair of metal surfaces ormetal plates to bond the sealing tape to the joint while bending thesealing tape, wherein the sealing tape is made of a sealing-tapematerial containing an unvulcanized rubber-base material and itsvulcanization accelerator, the sealing tape assuming an elongated shapewith a bottom surface and a predetermined thickness measured in adirection perpendicular to the bottom surface; and

applying, in a painting process, a paint to an upper surface of thesealing tape thus bent and bonded to the joint, wherein the paint issubjected to a heating process in which the sealing tape thus bent andbonded is vulcanized to become a final rubber product with a fixedresilient shape thus bent and bonded.

In this method of repairs with the sealing tape, the sealing tape hasits bottom surface bonded to the joint of the metal surfaces, which isfollowed by the the painting process accompanied with the heatingprocess for vulcanizing the sealing tape. Consequently, the sealing tapesubjected to the hearing process is vulcanized to become a final rubberproduct assuming a fixed resilient shape thus bent and bonded, whichenables the sealing tape thus vulcanized to resiliently keep its finalshape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an embodiment of the sealing tape of thepresent invention;

FIG. 2 is a schematic diagram of an embodiment of an apparatus of thepresent invention for carrying out an embodiment of the method of thepresent invention for producing the sealing tape shown in FIG. 1;

FIG. 3 is a perspective view of the roll-type cutter for cutting thesquare-shaped sheet in the method of the present invention for producingthe sealing tape shown in FIG. 1;

FIG. 4 is a side view of the roll-type cutter used in the method of thepresent invention illustrated in FIG. 2;

FIG. 5 is a cross-sectional view of the sealing tape shown in FIG. 1,illustrating a forming process of the sealing tape conducted in thesubstantially square-shaped sheet cutting step of the method of thepresent invention shown in FIG. 2;

FIG. 6 is a perspective view of a winding process for winding thesubstantially square-shaped sheet into a rolled sheet;

FIG. 7 is a perspective view of another embodiment of the apparatus ofthe present invention for carrying out the method of the presentinvention for producing the sealing tape shown in FIG. 1;

FIG. 8 is a plan view of the roll-type cutter used in the presentinvention;

FIG. 9 is a plan view of a guide roll used in the present invention;

FIG. 10(a) is a schematic diagram illustrating the substantiallysquare-shaped sheet cutting step conducted in the method of the presentinvention;

FIG. 10(b) is a schematic diagram illustrating a lengthwise trimmingstep for trimming lengthwise the opposite corner portion, in crosssection, of an upper surface of the sealing tape by means of a roll-typegrinding means;

FIG. 11 is a perspective view of another embodiment of the sealing tapeof the present invention;

FIG. 12 is a perspective view of the inside of a door, illustrating thesealing tape applied to a joint shoulder portion of metal plates in thedoor;

FIG. 13 is a cross-sectional view of the joint shoulder portion of themetal plates, to which portion the sealing tape has been applied;

FIG. 14 is a perspective view of a conventional sealing tape; and

FIG. 15 is a cross-sectional view of the joint shoulder portion of themetal plates, to which portion a sealing agent has been applied.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinbelow, the present invention will be described in detail withreference to the accompanying drawings.

FIG. 1 shows a perspective view of a first embodiment of a sealing tape10 of the present invention. The sealing tape 10 is made of asealing-tape material which contains an unvulcanized rubber-basematerial, a vulcanization accelerator thereof, an anti-oxidizing agent,a pigment and a bulk filler. The sealing tape 10 assumes an elongatedshape with an upper and a lower surface. The lower surface forms a flatbottom surface 1, while the upper surface forms a circularly-curvedsurface 2. The sealing tape 10 has a predetermined thickness measured ina direction perpendicular to the bottom surface 1, and is in anunvulcanized state.

Applied to the bottom surface 1 of the sealing tape 10 is an adhesivelayer 3 which is covered with a protective tape 4 to keep the sealingtape 10 in an unvulcanized state or condition which enables the adhesivelayer 3 to be firmly bonded to the bottom surface 1 of the sealing tape10. At this time, the surface roughness in the bottom surface 1 of thesealing tape 10, which is in the unvulcanized state or condition,facilitates the application of the adhesive layer 3 to the bottomsurface 1. Consequently, in the present invention, it is possible toeliminate a cumbersome application working of a double-faced adhesivetape to the bottom surface 1 of the sealing tape 10, which reduces themanufacturing cost. However, in the present invention, it is alsopossible to use such conventional double-faced adhesive tape in place ofthe adhesive 3 layer described above.

The protective tape 4 covering the adhesive layer 3 enables the sealingtape 10 to be wound into a roll for convenience of storage.

On the other hand, the vulcanization accelerator, for example such assulfur oxides and the like, functions to vulcanize the unvulcanizedrubber-base material under the influence of heat generated in a heatingprocess. Due to the thus vulcanized rubber-base material, the sealingtape becomes to a final resilient rubber product assuming a fixedresilient shape. The present invention is characterized in that suchvulcanization of the sealing tape 10 is carried out in the heatingprocess accompanied with a painting process. The sealing tape 10 is inan unvulcanized state or condition before it is applied to the metalsurfaces.

The anti-oxidizing agent, for example such as polybutene and the like,is added to the sealing-tape material to improve the sealing tape inweatherability.

The pigment, for example such as titanium oxides and the like, is usedto pigment the sealing tape 10 with a desired color.

The bulk filler, for example such as calcium carbonate and the like, isused to swell the sealing-tape material therewith. Further, the bulkfiller functions to increase the sealing-tape material in strength.

The sealing tape 10 of the present invention is used to cover a jointportion of metal plates. More particularly, in the joint portion formedbetween adjacent edge portions of the metal plates, the sealing tape 10is bonded to one of the adjacent edge portions of the metal plates toextend along the edge portion, whereby water and dust are prevented fromentering through the other of the adjacent edge portions of the metalplates in the joint portion.

On the other hand, as for the sealing tape 10 of the present inventionwhich is in the unvulcanized state or condition described above, due toits properties, it is not possible to produce the sealing tape 10 in thesame method as that used in production of a conventional vulcanizedsealing tape shown in FIG. 14. In other words, in a conventional methodfor producing the conventional vulcanized sealing tape, a vulcanizedrubber-base material, which has been already heated to a predeterminedelevated temperature and therefore is capable of being molded, is filledin a cylinder having its bottom opening be equal in cross-sectionalshape to the conventional vulcanized elongated sealing tape, and thenextracted from the cylinder by means of a piston to assume an elongatedshape of a final vulcanized rubber product, i.e., conventional sealingtape.

However, when the unvulcanized rubber-base material is used andextracted from the cylinder in the conventional method described above,it is not possible for the unvulcanized rubber-base material to assume afixed shape as defined by the bottom opening of the cylinder, whichmakes it impossible to produce an elongated unvulcanized sealing tape.

In contrast with the above conventional method, in the method of thepresent invention for producing the elongated unvulcanized sealing tape,as shown in FIG. 2, a plurality of the following process steps are used:

A sealing-tape material preparing step 100 for preparing a sealing-tapematerial containing an unvulcanized rubber-base material and itsvulcanization accelerator together with an anti-oxidizing agent, apigment and a bulk filler;

A sealing-tape forming step 200 in which the sealing-tape material isformed into a substantially square-shaped sheet 201 while keeping itsunvulcanized condition;

An adhesive applying step 300 for applying an adhesive to a bottom ofthe substantially square-shaped sheet 201 through an adhesive sheet 301;and

A substantially square-shaped sheet cutting step 400 for cutting thesubstantially square-shaped sheet 201 backed with the adhesive oradhesive sheet 301 into at least one of the sealing tapes 10 each ofwhich assumes an elongated shape having a bottom surface 1 and apredetermined thickness measured in a direction perpendicular to thebottom surface 1 of the sealing tape 10, wherein the substantiallysquare-shaped sheet 201 is moved while having its upper surface broughtinto press-contact with a roll-type cutter 401 which is provided with atleast a pair of circular blades 402 axially spaced apart from each otherthrough an annular groove or concave portion 403 formed in a peripheralportion of the roll-type cutter 401.

In the sealing-tape material preparing step 100, the unvulcanizedrubber-base material and its vulcanization accelerator together with theanti-oxidizing agent, pigment and the bulk filler are loaded into ahopper 101 and mixed therein to prepare the sealing-tape material havinga temperature of approximately 50 degrees centigrade.

In the sealing-tape forming step 200, the thus prepared sealing-tapematerial is formed into the substantially square-shaped sheet 201 whilekeeping its unvulcanized state or condition. More, particularly, thesealing-tape material supplied from the hopper 101 is squeezed between apair of squeeze rolls 202 to become the substantially square-shapedsheet 201.

In this case, the unvulcanized state or condition of the sealing-tapematerial enables the sealing-tape material to be capable of being moldedinto a desired shape. Incidentally, the sealing-tape material in asemi-vulcanized state or condition may be used in the method of thepresent invention.

The substantially square-shaped sheet 201 has a flat bottom surfacewhich may be slightly circularly curved in a direction perpendicular tothe traveling direction of the sheet 201.

In the adhesive applying step 300, the adhesive is applied to the bottomsurface of the substantially square-shaped sheet 201 through theadhesive sheet 301. More particularly, prior to the adhesive applyingstep 300, the adhesive is applied to opposite surfaces of an adhesivesheet 301. Thereafter, a protective tape 302 is applied to each of theopposite surfaces of the adhesive sheet 301 which is then wound into aroll. In the adhesive applying step 300, one of the protective sheets302, which is oppositely disposed from the bottom surface of thesquare-shaped sheet 201 and applied to the adhesive sheet 301, is peeledoff from the roll or wound adhesive sheet 301 when the sheet 301 isapplied to the bottom surface of the square-shaped sheet 201, wherebythe adhesive sheet 301 is bonded to the bottom surface of thesquare-shaped sheet 201, as shown in FIG. 2. The application of theadhesive sheet 301 to the square-shaped sheet 201 should be carried outimmediately after completion of the sealing-tape forming step 200. Theadhesive sheet 301 thus bonded to the bottom surface of thesquare-shaped sheet 201 functions to keep the shape of the sheet 201constant, which enables the sheet 201 to be wound into a roll forstorage.

In the square-shaped sheet cutting step 400, as shown in FIGS. 2 and 3,the square-shaped sheet 201 travels along a stand 410 in a condition inwhich the sheet 201 has its upper surface brought into press-contactwith the roll-type cutter 401 which is rotatably driven counterclockwiseas viewed in FIG. 2, so that the square-shaped sheet 201 is cut into aplurality of the sealing tapes 10 of the present invention at a time. Inother words, as shown in FIG. 4, since the roll-type cutter 401 isprovided with a plurality of circular blades 402 axially spaced apartfrom each other through the annular groove or concave portion 403 formedin the peripheral portion of the cutter 401, the substantiallysquare-shaped sheet 201 is cut into the plurality of sealing tapes 10each of which assumes an elongated shape having the bottom surface 1 anda predetermined thickness measured in a direction perpendicular to thebottom surface 1 of the sealing tape 10.

The bottom surface 1 of the sealing tape 10 is flat, and may be slightlycircularly curved in a direction perpendicular to a longitudinal axis ofthe elongated sealing tape 10.

A maximum depth h of the annular concave portion 403 of the roll-typecutter 401 is larger than the thickness d of the square-shaped sheet201, as shown in FIG. 5. Consequently, when the square-shaped sheet 201is squeezed and cut into the sealing tapes 10 by the roll-type cutter401, upper opposite corner portions of each of pieces X (shown in crosssection in FIG. 5) of the square-shaped sheet 201 are squeezed to forman upper circularly curved portion of a barrel-roof type form Y (shownin cross section in FIG. 5) of the sealing tape 10. In practice, theupper circularly curved portion of the barrel-roof type form Y isslightly larger in cross-sectional area than the piece X of thesquare-shaped sheet 201, which prevents the sealing-tape material fromoverflowing the annular concave portion 403.

As described above, in the method of the present invention, thesquare-shaped sheet 201 travels from the left to the right (as viewed inFIG. 2), and squeezed and cut into the plurality of the unvulcanizedsealing tapes 10 by means of the roll-type cutter 401.

In the above embodiment of the present invention, although the annularconcave portion 403 of the roll-type cutter 401 assumes the circularlycurved shape in cross section as is clear from FIG. 4, it is alsopossible for the annular concave portion 403 to assume any other desiredshape, which enables the sealing tape 10 being produced to have itsupper surface shaped into the same desired shape described above.

Now, another embodiment of the method of the present invention forproducing the sealing tape 10 will be described.

This another embodiment of the method of the present invention comprisesthe sealing-tape material preparing step 100, sealing-tape forming step200 and the adhesive applying step 300 all described above. As shown inFIG. 6, after completion of the adhesive applying step 300, thesquare-shaped sheet 201 is wound into a roll 203 for storage. By meansof a pair of pressure rolls 303, 304, the adhesive sheet 301 is bondedto the square-shaped sheet 201. In other words, the square-shaped sheet201 is backed with the adhesive sheet 301.

After that, as shown in FIG. 7, a leading end portion of the roll 203(i.e., the rolled square-shaped sheet 201) is pulled rightward to unwindthe roll 203, so that the square-shaped sheet 201 thus unwound is spreadon the stand 410 flat by means of a pair of holding rolls 305, 306.

After that, the square-shaped sheet 201 thus flattened travels on thestand 410 rightward and is pinched between the roll-type cutter 404 anda pressure roll 405 oppositely disposed from the cutter 404 as shown inFIG. 7, so that the square-shaped sheet cutting step 400 is realized. Asshown in FIG. 8, the roll-type cutter 404 is provided with a cylindricalbarrel portion 404a on which fixedly mounted are a plurality of circularblades 404b which are spaced apart from each other at equal intervals.Formed between adjacent ones of the circular blades 404b on thecylindrical barrel portion 404a, is an annular groove or concave portiona depth of which is larger than the thickness of the square-shaped sheet201. Consequently, when the roll-type cutter 404 is brought intopress-contact with the square-shaped sheet 201, the sheet 201 is cutinto a plurality of elongated sealing tapes 11 each of which assumes asubstantially square shape with a predetermined thickness in crosssection, as shown in FIG. 10(a).

Then, the sealing tapes 11 thus obtained are guided and aligned withtheir traveling paths by means of a guide roll 501 shown in FIG. 9. Theguide roll 501 is provided with a cylindrical barrel portion 501a onwhich a plurality of circular partition members 501b are fixedly mountedin a manner such that they 501b are spaced apart from each other atequal intervals to permit each of the sealing tapes 11 to be received ina space formed between adjacent ones of the circular partition members501b of the guide roll 501a. A height of the partition member 501b islarger than that (i.e., height or thickness) of the square-shaped sheet201 or sealing tape 11. A pressure roll 502 following the guide roll 501is then brought into press-contact with upper surfaces of the sealingtapes 11 to eliminate a difference in height between these tapes 11 onthe stand 410.

Then, as shown in FIG. 10(b), each of the sealing tapes 11 thus alignedhas its upper opposite corner portions 11a trimmed by a roll-typegrinder or cutter 503 a rotational speed of which is far larger than thetraveling speed of the sealing tapes 11. This grinder or cutter 503 isprovided with a cylindrical barrel portion. Formed in an outerperipheral portion of the grinder or cutter 503 are a plurality ofannular grooves or concave portions 504 each of which extends in acircumferential direction of the grinder or cutter 503 and has acircularly-curved surface in cross section. Consequently, aftercompletion of the trimming operation conducted by the grinder or cutter503, the sealing tape 10 having a circularly-curved upper surface incross section is obtained, as shown in FIG. 1 or in dotted lines in FIG.10(b). The grinder or cutter 503 may have the surface of each of itsannular groove or concave portions 504 constructed of a filing means,and assume the same shape as that of the roll-type cutter shown in FIG.4, except that the depth of the groove or concave portion 504 is equalto the height of the sealing tape 11.

On the other hand, a vacuum conduit 601 is located directly upstream ofthe roll-type grinder or cutter 503 to suck up dust and tape filingsremoved by the grinder or cutter 503. A press roll 602 is locateddirectly downstream of the roll-type grinder or cutter 503 to eliminatea difference in height between the sealing tapes 11. After that, each ofthe sealing tapes 11 passed through the press roll 602 is wound on atake-up roll 603 which is rotatably mounted on the stand 410.

In this embodiment of the present invention, the roll-type grinder orcutter 503 is rotated clockwise, i.e., in a direction opposite to thetraveling direction of the sealing tapes 11, as viewed in FIG. 7.However, it is also possible for the grinder or cutter 503 to rotatecounterclockwise, provided that the rotational speed of the grinder orcutter 503 is far larger than the traveling speed of the sealing tapes11.

Now, a method of repairs with the sealing tape 10 thus obtainedaccording to the present invention will be described.

When a car body panel is damaged, it is necessary to repair such damagedpanel. In this repair, a sheet metal repair is first conducted. Afterthat, according to the present invention, the sealing tape 10 (shown inFIG. 1) is cut into a piece having a desired length. The adhesive layer3 of the bottom surface 1 of The thus obtained piece of the sealing tape10 with the desired length (hereinafter simply referred to as thesealing tape) is then applied to a joint portion between metal plateswhile peeled from its protective sheet 4 (shown in FIG. 1), so that thejoint portion of the metal plates is covered with and bonded to thesealing tape 10.

More specifically, in the joint portion, one of the metal plates has itssurface abut on a surface of the other. Consequently, when the sealingtape 10 is applied and bonded to one of the metal plates in the jointportion, it is possible to prevent water and dust from entering theinterior of the joint portion. As described above, the sealing tape 10of the present invention is capable of hermetically sealing the jointportion of the metal plate.

Since the sealing tape 10 is in the unvulcanized state or condition andtherefore capable of being molded into any desired shape, it is alsopossible to bend the sealing tape 10 when the tape 10 is applied to thejoint portion of the metal plates.

After completion of the application of the sealing tape 10 to the jointportion of the metal plate, a body color paint is applied to the jointportion, wherein: the paint is sprayed on the joint portion to form apaint layer thereon; and, thereafter, a forced heating process forstabilizing the paint layer thus applied is conducted in a spray boothat a temperature of approximately 70 degrees centigrade for at leasthalf an hour. Consequently, it is possible to vulcanize the sealing tape10 in the forced heating process. After completion of the forced heatingprocess, the sealing tape 10 having been vulcanized is capable ofresiliently keeping its final shape constant even when subjected to anexternal force.

Since the sealing tape 10 is in the unvulcanized condition, the sealingtape 10 is capable of being bonded to any desired object and beingfreely varied in shape. Even when the sealing tape 10 is bent to adesired shape along the joint portion of the metal plates, there is nofear that the thus bent portion of the sealing tape 10 slacks orseparates from the joint portion of the metal plates.

Further, at this time, the bottom surface 1 (which is coated with theadhesive layer 3) of the sealing tape 10 is varied in shape when pressedagainst the joint portion of the metal plates, which enables theadhesive layer 3 bonded to the bottom surface 1 of the sealing tape 10to fit the joint portion of the metal plates. Consequently, even whenthe joint portion of the metal plates is constructed of a steppedsurface, it is also possible for the sealing tape 10 of the presentinvention to fit such stepped joint surface of the joint portion.

After completion of the application of the sealing tape 10 to the jointportion of the metal plates, the sealing tape 10 applied to the jointportion is subjected to a painting process, in which the sealing tape 10is painted and then heated, and, therefore vulcanized, whereby the thusvulcanized sealing tape 10 is capable of resiliently keeping its bentshape constant.

Therefore, the method of repairs of the present invention may eliminatesa conventional vulcanization step, because the conventional paintingprocess is accompanied with its own heating step which enables thesealing tape 10 to be vulcanized.

FIG. 11 is another embodiment of the sealing tape 10 of the presentinvention. The sealing tape 10 shown in FIG. 11 is made of the samesealing-tape material as that of the sealing tape 10 shown in FIG. 1.The big difference between these sealing tapes 10 is that the formershown in FIG. 11 has a stepped bottom surface while the latter has aflat bottom surface 1. Incidentally, in the embodiment of the sealingtape 10 shown in FIG. 11, both an adhesive layer and a protective sheetcorresponding to those 3 and 4 shown in FIG. 1 are omitted toperspicuity.

More particularly, the stepped bottom surface of the sealing tape 10shown in FIG. 11 is constructed of: a first flat bottom surface 11; asecond flat bottom surface 12, which is lower than the first flat bottomsurface 11; and, a connecting surface 13 therebetween, The connectingsurface 13 extends in a direction perpendicular to the bottom surfaces11, 12 therebetween.

As is clear from FIG. 11, the sealing tape 10 has: an uppercircularly-curved convex surface 14, which is oppositely disposed fromthe first flat bottom surface 11; a flange surface 15, which isoppositely disposed from the second flat bottom surface 12; and, a rootportion 16, which is disposed between the convex surface 14 and theflange surface 15 to extend along the entire length of the sealing tape10.

The stepped bottom surface of the sealing tape 10 having the aboveconstruction facilitates application of this sealing tape 10 to astepped joint portion formed between the metal plates. For example, asshown in FIG. 13, a second metal plate B has its edge portion fitted ina bent end portion C of a first metal plate "A", so that a stepped jointportion D is formed therebetween. When the joint portion D is coatedlengthwise with the sealing tape 10 shown in FIG. 11, this sealing tape10 is applied to the joint portion D in a manner such that: the firstflat bottom surface 11 oppositely disposed from the convex surface 14 ofthe sealing tape 10 is bonded to the metal plate "A"; and, the secondflat bottom surface 12 oppositely disposed from the flange surface 15 ofthe sealing tape 10 is bonded to the metal plate B.

Consequently, the sealing tape 10 may have its bottom surfaces 11, 12and connecting surface 13 therebetween perfectly fit the stepped jointportion D of the metal plates "A", B without fail, whereby the jointportion D is hermetically sealed.

EXAMPLE

Now, an example of the sealing tape 10, 11 of the present invention willbe described.

Mixed in the hopper 101 at a temperature of approximately 50 degreescentigrade to prepare the sealing-tape material were: a 40 parts byweight of the unvulcanized rubber-base material; a 10 parts by weight ofthe sulfur oxides as the vulcanization accelerator; a 12 parts by weightof polybutene as the anti-oxidizing agent; a 10 parts by weight oftitanium oxides as the pigment; and, a 28 parts by weight of calciumcarbonate as the bulk filler.

Namely, the composition of the sealing-tape material is shown in thefollowing Table 1:

                  (TABLE 1)                                                       ______________________________________                                        rubber-base material                                                                         40 parts by weight                                             sulfur oxides  10 parts by weight                                             polybutene     12 parts by weight                                             titanium oxides                                                                              10 parts by weight                                             calcium carbonate                                                                            28 parts by weight                                             ______________________________________                                    

As shown in FIG. 2, the sealing-tape material thus prepared was thenformed into the substantially square-shaped sheet 201 having a length of12 centimeters in the forming step 200. Immediately after completion ofthis forming step 200, the square-shaped sheet 201 was backed with theadhesive sheet 301 coated with an adhesive. After that, thesquare-shaped sheet 201 was cut into a plurality of sealing tapes 10 ata temperature of approximately 40 degrees centigrade at a time by meansof the roll-type cutter 401 on the stand 410.

The thus obtained unvulcanized sealing tape 10 was applied to a bentjoint portion formed between metal plates. After application of thesealing tape 10 to the bent joint portion, any slack or any separationof the sealing tape 10 was not found in such bent joint portion of themetal plates. Then, a painting process was conducted, in which thesealing tape 10 applied to the bent joint portion of the metal plateswas subjected to a heating process, and, therefore vulcanized. Afterthat, the sealing tape 10 thus vulcanized was found to be capable ofresiliently keeping its fixed shape bent along the bent joint portion ofthe metal plates.

In the unvulcanized sealing tape 10 of the present invention, due to itsunvulcanized condition, the sealing tape 10 is capable of being bondedto any object and also capable of varying its shape so as to fit anyobject's shape, which eliminate any fear of slack and separation of thesealing tape 10 applied to the object. Consequently, it is possible toapply the sealing tape 10, 11 of the present invention to any object inan easy manner, which improves the sealing tape 10, 11 of the presentinvention applied to the object in appearance in finishing.

In the method of the present invention for producing the sealing tape10, 11, since the square-shaped sheet 201 is continuously cut by theroll-type cutter 401 while traveling on the stand 410, it is possible toobtain the elongated unvulcanized sealing tapes 10, 11.

Due to the annular grooves or concave portions 403 of the cutter 401, itis possible to have the upper surface of the sealing tape 10, 11 of thepresent invention formed into a circularly-curved convex shape orbarrel-roof like shape in cross section, which enables the sealing tape10, 11 to be well adapted to its use.

In the method of the present invention for repairs, the sealing tape 10,11 is bent while applied to the joint portion of the metal plates. Afterthat, the sealing tape 10, 11 of the present invention applied to thejoint portion is subjected to the painting process, in which the sealingtape 10, 11 is heated, and, therefore vulcanized. Consequently, the thusvulcanized sealing tape 10, 11 of the present invention is capable ofresiliently keeping its fixed shape formed when applied to the jointportion of the metal plates in repairs. Due to the above paintingprocess accompanied with the heating step, it is possible for the methodof repairs of the present invention to eliminate a conventionalindependent vulcanization process.

What is claimed is:
 1. In an elongated sealing tape for repairing adeformed joint of car body panels so as to have said deformed jointreturn to an original shape as that of a new car, said joint beingdisposed between a pair of metal surfaces or metal plates inside saidcar body panels, said sealing tape being applied to said joint aftercompletion of a repair in shape of said joint, the improvementcomprising:said sealing tape containing a rubber-base material and itsvulcanization accelerator so as to be capable of being bent atsubstantially right angles when said sealing tape is applied to saidjoint; and in a condition in which said sealing tape is still notvulcanized, said sealing tape having a predetermined thickness in adirection perpendicular to a bottom surface, and having a curved surfacein an upper surface.
 2. The sealing tape as set forth in claim 1,wherein:added to said unvulcanized rubber-base material together withsaid vulcanization accelerator is an anti-oxidizing agent.
 3. Thesealing tape as set forth in claim 1, wherein:an adhesive is applied tosaid bottom surface of said sealing tape.
 4. The sealing tape as setforth in claim 1, wherein:said bottom surface is a stepped surface.